Quantitative Assessment of Microcollateral Recruitment During Coronary Occlusion Using Real-time Intravenous Myocardial Contrast Echocardiography

Background Residual collateral-derived myocardial blood flow (MBF) (A × β) is important to protect against myocardial ischemia after acute coronary occlusion. Methods Recruitment of microcollateral was assessed in 22 dogs with left circumflex coronary artery occlusion by analysis of MBF and regional wall thickening (WT) using real-time myocardial contrast echocardiography. Results Video intensity and WT at the center of risk area were significantly lower than those at the border of risk area. The video intensity, A value, β value, and MBF correlated well with WT after left circumflex coronary artery occlusion. The WT of the area with above 25% of normal MBF was preserved and was higher than that at below 25%. However, the deterioration of WT was not distinguished according to A value. Conclusion Real-time myocardial contrast echocardiography is a useful noninvasive method to evaluate collateral-derived MBF, which can be a reliable index of protection against myocardial ischemia.